Steady State Theory The steady state theory was created by Herman Bondi in and it shows the univese while it is gradually expanding does not change it's shape or structure and that atoms are newly created each year allowing this expansion to go on expedentially without any part of the Universe being changed or moved and the density staying always the same. With this theory there is no beginning or ending to time and things always have been.
The Big Bang Theory
At the wall of the cosmic bubble, symmetry continued to break and the wall moved outward, making the bubble grow. Just inside this wall the Higgs fields were releasing their energy as they decayed. So the bubble was gradually filled with energy. This energy filled the Cosmos with fields, particles and radiation. This is called the Big Bang
The theory proposes that 13.7 billion years ago, an atom called a singularity exploded and began to grow at an increasing rate, the ball of protons and neutrons moving about, and the whole thing went through many stages of heating and cooling before cooling to allow the protons and neutrons to form atoms of gas which eventually became galaxies. Here gravity kicks in, and starts to pull everything apart until they separate in to different galaxies and the leftover gas in to stars and planets. The first clear hint that the universe might change as time passes came in 1917 when Albert Einstein developed his General Theory of Relativity. Einstein realised that his equations said that the universe must be either expanding or contracting, but it could not be standing still, because if it were then gravity would attract all the galaxies towards one another.
It is necessary to understand that the Big Bang did not begin as a huge explosion within the universe, the Big Bang created the universe. A popular misunderstanding is that it happened within the universe and that it is expanding through it.
The Oscillatory Universe Theory The oscillatory universe theory is partially an off shoot of the big bang theory, created by Richard Tolman who says that in a closed universe, it would at one point in time reach a stage when it was too big and would start shrinking and contracting slowly at first, but gathering speed, and heat until what is deemed the "Big Crunch" will happen and everything will colapse back in to itself. Some believe though that this would not be the end though, and that the universe would then begin it's expansion again with another big bang and so on.This theory was very popular in the 70's and 60's, but soon after scientists began questioning it and found a few major flaws in it to make this model impossible, one being that the Universe is not closed and could therefore expand forever and also that is completely ignores the second rule of thermodynamics which says that useable energy decreases over time and would allow for the Universe to slowly fall apart.
The Superstring Theory
This final idea states that particles are created by microscopic strings which when plucked a certain way give off a specific pitch/atom and by these strings vibrating the universe was made. There are tons upon tons of String theories which have been made over time all slightly different, but the idea is the same of strings mesured in placks whose vibrations create the forces of nature and the atoms around us,
There are many more theories, but it would take forever to list them all. Some are still believed, while others have been disproved, but that's really what a theory is, isn't it. It's an idea, someone thinking about something and tries to explain it and these are all very good at doing just that.
Creation of the Universe
By: Mason and Devon
Steady State Theory
The steady state theory was created by Herman Bondi in and it shows the univese while it is gradually expanding does not change it's shape or structure and that atoms are newly created each year allowing this expansion to go on expedentially without any part of the Universe being changed or moved and the density staying always the same. With this theory there is no beginning or ending to time and things always have been.
The Big Bang Theory
At the wall of the cosmic bubble, symmetry continued to break and the wall moved outward, making the bubble grow. Just inside this wall the Higgs fields were releasing their energy as they decayed. So the bubble was gradually filled with energy. This energy filled the Cosmos with fields, particles and radiation. This is called the Big Bang
The theory proposes that 13.7 billion years ago, an atom called a singularity exploded and began to grow at an increasing rate, the ball of protons and neutrons moving about, and the whole thing went through many stages of heating and cooling before cooling to allow the protons and neutrons to form atoms of gas which eventually became galaxies. Here gravity kicks in, and starts to pull everything apart until they separate in to different galaxies and the leftover gas in to stars and planets. The first clear hint that the universe might change as time passes came in 1917 when Albert Einstein developed his General Theory of Relativity. Einstein realised that his equations said that the universe must be either expanding or contracting, but it could not be standing still, because if it were then gravity would attract all the galaxies towards one another.
It is necessary to understand that the Big Bang did not begin as a huge explosion within the universe, the Big Bang created the universe. A popular misunderstanding is that it happened within the universe and that it is expanding through it.
The Oscillatory Universe Theory
The oscillatory universe theory is partially an off shoot of the big bang theory, created by Richard Tolman who says that in a closed universe, it would at one point in time reach a stage when it was too big and would start shrinking and contracting slowly at first, but gathering speed, and heat until what is deemed the "Big Crunch" will happen and everything will colapse back in to itself. Some believe though that this would not be the end though, and that the universe would then begin it's expansion again with another big bang and so on.This theory was very popular in the 70's and 60's, but soon after scientists began questioning it and found a few major flaws in it to make this model impossible, one being that the Universe is not closed and could therefore expand forever and also that is completely ignores the second rule of thermodynamics which says that useable energy decreases over time and would allow for the Universe to slowly fall apart.
The Superstring Theory
This final idea states that particles are created by microscopic strings which when plucked a certain way give off a specific pitch/atom and by these strings vibrating the universe was made. There are tons upon tons of String theories which have been made over time all slightly different, but the idea is the same of strings mesured in placks whose vibrations create the forces of nature and the atoms around us,
There are many more theories, but it would take forever to list them all. Some are still believed, while others have been disproved, but that's really what a theory is, isn't it. It's an idea, someone thinking about something and tries to explain it and these are all very good at doing just that.
Citations
http://www.thekeyboard.org.uk
http://en.wikipedia.org/wiki/Steady_state_theory
http://ssscott.tripod.com/BigBang.htmlhttp://www.allaboutcreation.org/oscillating-universe-theory-faq.htmhttp://www.superstringtheory.com/